1. Field
The present disclosure relates to sound suppression and acoustical privacy in architectural structures. More particularly, the disclosure is directed to noise attenuation in flanking paths between the ends of interior separations and mullions in curtain wall and storefront constructions.
2. Description of the Prior Art
By way of background, commercial building codes typically impose acoustic privacy restrictions that limit the amount of noise permitted to pass through interior separations. For example, section 1207.2 of the International Building Code (IBC) imposes the following requirement for air-borne sound:
“Walls, partitions and floor/ceiling assemblies separating dwelling units from each other or from public or service areas shall have a sound transmission class (STC) of not less than 50 (45 if field tested) for air-borne noise when tested in accordance with ASTM E 90.”
In curtain wall and storefront constructions, unsealed interfaces between the ends of interior separations and the exterior mullions produce “flanking paths” for air-borne sound that may severely compromise the transmission loss intended for the separation. The sound that invades through such flanking paths compromises the acoustic integrity of the separations irrespective of the acoustic attenuation qualities of the separation structures themselves. Applicant submits that this issue needs to be addressed if adequate levels of privacy and confidentiality are to be attained.